Extension-ladder



J. L. CRAFTS. EXTENSION LADDER.

(No Model.)

12.1887. Big. 5

Patented A -8 No. 361,137. Fig.1.

witnesses N. PETERS. Fhnlo-Lihognphsr. Washingm D. C.

UNITED STATES PATENT OFFICE.

JOHN L. CRAFTS, OF SOMERVILLE, MASSACHUSETTS.

EXTENSION-LADDER.

SPECIFICATION forming part of Letters Patent No. 361,137, dated April12, 1887.

To all whom itmwy concern.-

Be it known that I, JorrNL. CRAFTS, of Somerville, inthe county ofMiddlesex and State of Massachusetts, have invented certain new anduseful Improvements in Extensionghadders, of which the following is aspecificaion.

My invention relates to what are commonly known as extension-laddersthatis, ladders having a movable section which is proccted in prolongationof the main section.

It is the object of my invention to so im prove the contrivances forholding the movable section in projected position as to render theiroperation certain and effective irrespective of the position in whichthe ladder may by chance or ofnecessity be held.

It is also the object of my invention to simplify and otherwise improvethe means whereby the movable or upper section is projected or raised.

It is also the object of my invention to so modify the construction ofthe means which permit of the lowering of the upper or movable sectionas to permit this operation to be readily and easily accomplished.

It is also the object of my invention to improve the construction of therounds of the ladder ,-as also the manner of securing the to the sidepieces.

I will ,now proceed to describe my invention, so that others may be ableto make and use the same, reference being had to the accompanyingdrawings, and to the letters of reference marked thereon, forming a partof this specification, in which drawings- Figure 1 is a front elevationof my improved extension-ladder. Fig. 2 is a section on the line a: m,Fig. 1, looking in the direction of the arrow. Figs. 3 and 4 aresections on the line :20 00, Fig. 1, looking in a direction opposite tothe arrow. Fig. 5 is a rear view. Fig. 6 is a section on the line 1 y,Fig. 1. Fig. 7 represents a section on line z z, Fig. 2, showing adifferent form of cord-conducting round.

Similar letters of reference indicate similar parts in all the views.

In the drawings, A represents the lower or supporting section, andB theupper or sliding section. Both sections comprise side pieces, a a, ofcommon or suitable construction, with rounds I) 72 arranged at suitableintervals Application filed January 4, 1887. Serial No. 223,350. (Nomodel.)

the latter sect-ion, as shown most clearly in g 0 represent cleats orlips secured at their rearward or inner ends to section A, and extendingoutward and over the side pieces of section B, to guide it in itslongitudinal movements. V

d indicates a cord, rope, or chain secured at one end, as ate, to theupper end of one ofthe side pieces of lower section, A, and extendingdown and around a pulley, f, journaled in aslot in the lower portion ofone of the side pieces of the upper section, B, through a hollow round,h, to and around another pulley, i, in the opposite side piece of theopposite section, up and over a pulley, k, adapted to turn on a stud, l,at the upper end of the side piece of section B opposite that at whichthe other end of the cord or rope is secured. It will now be seen thatby drawing on the freevend of the cord or rope depending from pulley lasection B may be moved up on the rounds of section A, guided by thecleats or lips c, and so extended until stopped by the contact ofbrackets g j with lower cleats, c.

m m indicate hooks rigidly secured at their upper ends to a round, n,adapted to turn in the side pieces of sectionA. The lower ends of saidhooks are extended somewhat, as shown at 0, and the outer face of saidextension and ends are inclined or rounded, as also represented in Figs.2, 3, and 4..

9 indicates a nut or collar, also rigidly secured to the round at, andto said not or collar is attached a spring, q, connected at its upperend, as at p, with the upper round, 0', of section A, said springoperating with a tendency to throw the lower ends of the hooks m anoutward or forward, so that when the upper section, B, is moved upwardon. the lower section, A, the rounds of said uppersection willsuccessively bear on the inclined or rounded ends of hooks in anddisplace or press said hooks backward against the tension of said springq. Said spring forces the hooks outwardly after each upwardly-movinground passes and releases said hooks, so that if the upper section beallowed to gravitate just after one of its rounds has released the hookssaid round will be caught and supported by the hooks. By thus securingthe hooks to a round adapted to rotate in its bearings and arranging thespring q to so operate the round to which the hooks are attached as tokeep them pressed outward or forward, I provide a construction in whichthere is little or no liability of ice freezing on the device frominterfering with the operation of the hooks-a difficulty experienced instructures heretofore in use.

i t represent dogs pivoted one to each hook m, on the inner sidethereof. Said dogs are so constructed that their outer ends normallyproject across the path in which the rounds of the upper section move,and are displaced or pressed back by the upward movement of the roundsof said section, the outer ends of the dogs swinging outwardly undereach round that passes and releases said dogs. A spring, a, is securedto the inner end of each of said dogs and rests at its forward and upperend against the rear face of the shanks of hooks m. The form andarrangement of springs to are such as to hold the outer ends of dogstwithin the line of travel of the rounds of section B as said section ismoved or projected on section A.

Each hook m is provided with alaterally or inwardly projecting lip, o,in such relation to the dogs at that when the latter are turned on theirpivots w by the downward movement of a round of the upper sectionbearing on said dogs the outer ends of said dogs will bear on said lips'21 of the hooks in and force the hooks backward, as hereinafterdescribed.

The operation of my invention will now be readily understood. By drawingdown on the free end of cord (1 section B will be raised or projected onsection A,the rounds of theformer section engaging the inclined face ofand press ing back hooks m, as described, and in like manner engagingand passing the upper forward ends of dogs t. When the upper section hasbeen raised to the desired extent, and just after a round thereof haspassed over and released the hooks in, said section is lowered slightly,when the hooks m, pressed forward by the tension of spring q, willengage said round and effectually hold said upper section in raised orextended position. Vhen it is desired to lower the upper or movablesection, said section is raised until the round held by the hooks mpasses just above the outer upper ends of dogs 15 and is there allowedto descend by gravitation, bringing the rounds above the dogssuccessively in contact with the outer upper ends of said dogs, forcingthem over into contact with the lips 22 of hooks m, as indicated in Fig.4, and forcing the hooks back, so that the rounds pass the hooks withoutbeing engaged thereby. The hooks, being arranged on the upper end of thelower section and held pressed outward by spring q, are certain at alltimes to be in position to engage the rounds of the upper or movablesection without regard to the position of the ladder. The springs to onthe dogs also insure the proper operative position of said dogs,whatever may be the position of the ladder.

The rounds'b, being made hollow, are light and strong, and by providingthe ends of said rounds with right and left hand screw-threads the sidepieces can be adjusted, as has been explained, with the utmost nicety,while the most convenient means possible are provided for securing therounds to their respective side pieces.

While I have been particular in describing the form and relationship ofthe various parts, it is obvious that these may be varied within thelimits of mechanical skill without departing from the nature or spiritof the invention.

It will be seen that the means for raising and holding the slidingsection of the ladder are arranged at and near the side pieces oftheladder, so that the space between said pieces is unobstructed. Theladder is thus made more convenient to use than extension-ladders inwhich the raising and holding devices are located midway between theside pieces, as usual.

I prefer to make the cord-conducting round of the upper section in theform of a hollow casting, (see Fig. 7,) open at its lower side andprovided at its ends with enlarged chambers f 2 f, which are fitted ininortises cut in the side pieces of the upper section. The pulleys ffare journaled in said chambers, and as the chambers are contained in theside pieces they are protected by the latter against injury, and do notproject so as to inj ure the operator when the upper section is suddenlylowered.

Having thus described my invention, what I claim is- 1. Anextension-ladder consisting of a lower section and an upper or movablesection, the upper rounds of the lower section being provided with oneor more hooks secured to a rotary round in said last-mentioned sectionand adapted to engage and hold the rounds of the upper section, and aspring connected at its lower end with said rotary round and at itsupper end toa rigid round in the same section, whereby the hooks may beheld pressed outward or forward, and ice freezing on the device will notbe liable to interfere with the operation of the spring, substantiallyas set forth.

2. In an extension-ladder, the combination of the upper or slidingsection, the lower or supporting section,the operating cord or chainsecured at one end to the upper portion of the lower section, andpassing thence downwardly and through a hollow round in the lowerportion of the upper section, and thence upwardly over a pulley at theupper portion of the lower section,its free end depending from saidpulley, and means, substantially as set forth, connected with the upperend of the lower section for engaging and holding the upper or movablesection, substantially as and for the purposes hereinbefore set forth.

3. An extension-ladder having an operating cord, rope, or chain attachedto the upper end of its lower or stationary section, and passing fromthence downward through a hollow round in the lower portion of the uppersection, and from thence upwardly over a pulley at the upper end of thelower section, substantially as set forth.

4.. The lower section, a cord, rope, or chain attached to the'upper endof one of the side pieces of said section, a pulley arranged in theupper end of the other side piece of said section,an upper sectionhaving a hollow round, and a pulley attached to each side piece at theends of said hollow round, said cord being arranged to pass over thepulleys of said upper section,through the hollow round thereof, and overthe pulley arranged in the upper end of one of the side pieces of thelower section, all constructed, combined, andarranged substantially asand for the purposes set forth.

5. The lower and upper sections, hooks m, round a, spring q, and round1', constructed, combined, and arranged substantiallyas and for thepurposes set forth.

6. Hooks 122, provided with lips 12, dogs t, pivoted to hooks m,andsprings u, constructed, combined, and arranged substantially as and forthe purposes hereinbefore set forth.

7. The upper section having the hollow round provided at its ends withpulley-containing chambers fitted in mortises in the side pieces of saidsection, as set forth.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, this 22d day of December, A. D.1886.

JOHN L. CRAFTS.

\Vitnesses:

O. F. BROWN, ARTHUR W. ORossLEr.

